The present invention relates to a driving mechanism adapted to drive vehicle accessory devices such as a hydraulic pump for a power steering device, an air pump, a vacuum pump or the like, and more particularly to a driving mechanism for starting an internal combustion engine and driving the vehicle accessory devices under the control of an electric current applied thereto from an electric power source.
In the case that such vehicle accessory devices as described above are driven in a usual manner by a prime mover of the vehicle, rotational speed of the accessory devices excessively increases in operation of the prime mover at a high speed, resulting in output torque losses of the prime mover. In the case that the accessory devices are driven by an electric motor, a high output torque is temporarily required only when the accessory devices are loaded in operation thereof, resulting in necessity of an electric motor of a large capacity.